Azo dyestuffs as photographic coupling components



Patented July 18, 1950 2,515,691 AZO DYESTUFFS As PHOTOGRAPHIC COUPLING COMPONENTS Jules Edmond Beersmans, Borgerhout-Antwerp, Belgium, assignor to Gevaert Photo-Producten N. V., Martsel-Antwerp, Belgium, a company of Belgium No Drawing. Application August 15, 1947, Serial No. 768,936. In Great Britain August 21, 1946 8 Claims. (Cl. 95-6) The present invention relates to the production of color photographic images for color photography and more particularly to dyestuff intermediates for use in color photographic processes, especially by the process known as color development. 1

It is known that a colored photographic image I may be formed simultaneously with the development of a silver image in an exposed photographic silver halide emulsion layer if an aromatic developing agent is used in the presence'of a color coupler which couples with th oxidation product of such developer produced during development to form quinone-imine or azomethine dyestuffs.

The formation of azomethine dyestuffs necessitates the presence of a color coupler which contains a reactive methylene group linked on both sides with an electro-negative group. The most commonly used electro-negative groups known from th literature are --CN, -CO, CS-, nitrophenyl, the residue of a nitrogen containing fiveor six-membered heterocyclic ring or a carbimide group =C=N as in a pyrazolone nucleus.

Many such color couplers have been described in the literature, but the requirements for a satisfactory color coupler are rather strict. If it is to be incorporated in a photographic emulsion layer in the course of manufacture it should not have any deleterious influence upon the sensitizers or stabilizers of the emulsion and neither the coupler itself nor the dyestuff derived from same should have any substantial tendency to diffuse from such layer either into adjacent layers of the photographic element or into processing baths. If the coupler is to be added to the developer, there are still many requirements which must be met; thus it must not produce color fog on development, it must be stable to the alkaline substances of the developing bath which in turn must be stable to the oxygen of the air and so on. The number of the couplers known does not yet suffice to allow a free choice in view of the required shade and intensity of the dyestufi formed on development while furthermore the possibility of producing the coupler at an economic price must be taken into consideratlon.

It is an object of the present invention to provide a new process for developing a reducible silver salt image in a photographic element by means of a developing agent in the presence of a color coupler.

Another object of the present invention is to provide a photographic material containing a new color couplen' A further object of the present invention is to provide a photographic developer containing a new color coupler. 1 i

Further objects will appear from the following description:

According to the present invention a valuable new class of color couplers is offered for the production of color photographic images by color development, which couplers contain a reactive methylene group linked on both sides to an electro-negative group, one of which is an 2.20 group. These couplers may correspond to one or other of the following probable general isomeric formulae:

2. alpha phenylazo acetyl acetic acid 3. phenylazo cyano acetic'acid coon 4. phenylazo acetonitrile 5. phenyl azo-nitro-rnethane r 6. p-nitro-phenyl azo-cyano acetic acid 7. alpha-naphthyl azo-cyano acetic acid.

either substituted 8. p-phenyl-azo-phenyl azo. aceton-itrile;

9. diphenylene-p-p'-bis(azo acetonitrile) 10. bis (phenylazo) acetonitiile;

ENG. @N lH N=NO Compounds: which: contain: the, group:

are for instance: hydrazone's or aldoses:

Lactose-phenyl-hydrazone, Maltose-phenylrhydrazone, ll-Arabinose-phenyl-ehydrazone,; d-Glucose-petolyl-hydrazone,

d-Glucose-2 :5-dich1oro -phen-yl-.-hydrazone, l-Arabinose-p bromo-phenyl-hydrazone.

Phenyl azo cyanacetic acid may be obtained by: saponifying phenyl: azocyanacetic acid ester by boiling for one hour in a 4% solution of NaOH ilI QmiXtUIB of equalproportions of alcohol. and water, Theproductmelts at 157 C. Itmay be decarb'oxylated. by prolonged boiling to form phenyl azo acetjonitrile. (cf. Bertini Gaz..Chem. Ital. 31 I579) Phenyl azo nitro methane may be obtainedv by allowing to reactisonitromethane and diazo benzene (Bamberger, Berichte 33; (1900) 206.0 and 34 (1901) 580).

p-Nitro phenyl azo cyan acetic acid may be obtained by heating the corresponding ester (prepared according to Ullman J. pr. Chem. 2, 51 (1895) 218) with 30 cc. NaOH 2 N and 30 cc. alcohol for onehour. The;precipitate formed is sucked oft and washed'witlralcohol; The sodium salt of the desired compound is obtained.

Bis(pheny1 azo). acetonitrilev may be" obtained by allowing to react 2 moldiazo-benzene and 1 mol cyanacetic" acid according to Weissbach J. pr. Chem. 2 67 400 or'Wedekind Ber. 30 2995.

According to the substituents in the molecule of the color couplers andtothe developingagent chosen, yellow; magenta, or cyan dyestuffs having widely varying, shades are obtained on color development. The new color couplers. may be included either in the developing solution or added to a, silver halide emulsion layer inthe course of manufacture, or in a water-permeable colloid layer coated next toasilver halide emulsionlayer or separated therefrom only by a thin water-permeable layer. Whernthey areincorporated in a photographic-layer, it is often' advantageous to introduce in their: molecule substituents rendering same difiusion-fast-such as, chains of more than five C atoms, biphenyl-groups or the like.

Example. 1

An exposed silverhalide emulsion layer is developed in a bath of the following composition:

NzN-diethyl-p-phenylen'ediamine hydrochloride gm 2 Sodium sulphite (crystals) gm Sodium carbonate (crystals) gm 60 Sodium hydroxide gm 2 Water tocm. 1000 Phenylazo cyanacetic acid gm 3 Methyl alcohol cm.

Foruse; Bis added to A.

After' fixing and eliminating the reduced silver, a transparent magenta dyestufi image is obtained.

Example 2 An. exposed silver. halide emulsion is. developed in. a bath containing the following substances:

N :N-diethyl-p-phenylene diamine hydrochloride n gm 2 Sodium sulphite (crystals) gm 25 Sodium carbonate (crystals) gm Sodium hydroxide gm 2 Water'to cm. 1000 Glucose-phenylhydrazone; -gm 3 Methyl alcohol 1 cm'. 30

For use B is. added to A.

After, fixing and eliminating the reduced silver; a transparent magenta dyestuff image is ob tained. I

Examplev 3 An: exposed. silver. halide emulsion layeris developedrin arbathof the-following compositions:

A NrNdiethyl-pphenylene diamine hydrol ide e.m 2 Sodium. sulphite (crystals) gm 25 Sodium carbonate (crystals) gm 60 Sodium hydroxide gm 2 Water to cm. 1000 B? Phenylazo'nitro' methane gm 3 Methyl; alcohol cm. 30

For use, B is addedfto A.

After fixing and eliminating the reduced silver, a'transparent magenta d'yestufi image is obtained.

Example 4 An exposed silver" halide. emulsion layer'is developed'in a bath-of the following composition:

Afterfixingand eliminating the reducedsilver, a transparent blue dyestuffimage is obtained;

Example. 5

Ant exposed silver halide emulsion-layer is developed in a bath of the following composition:

Hydroquinone gm 5 Sodium sulphite (crystals) gm 5 Sodium carbonate (crystals) gm 60 Water to cm. 1000 Phenylazo cyanacetic acid gm 2 Sodium carbonate 25 per cent cm. 20 Ethyl-alcohol cm. 30

For use, B is added to A.

After fixing and eliminating the reduced silver, a transparent yellow dyestuff image is obtained.

Although my invention is primarily concerned with color photographic processes wherein a dyestuff is formed by color coupling development with aromatic developing agents such as derivatives of phenylenediamines, aminophenols, polyoxybenzenes and hydrazines, it is also possible to use some of the color couplers of the invention in other color photographic processes: for instance in processes wherein the dyestuff is formed by coupling between the color coupler and a nitroso aniline or a diazo compound.

I claim:

1. A process of color photography which comprises developing a reducible silver salt image in a photographic element by means of an arcmatic developing agent in the presence of a color coupler capable of coupling with the development product of said developing agent and selected from the class consisting of compounds containing a reactive methylene group immediately linked to an azo group and to a group selected from the class consisting of a cyan group, a carbonyl group, a thiocarbonyl group, nitrophenyl, a residue of a nitrogen-containing heterocyclic ring having a free bond in'the 2- position with respect to the nitrogen atom, such residue having a free bond in the 4-position, a carbimide group a nitro group and a -CHOH- group, the hydrazone isomers of said compounds, and said compounds and isomers wherein a H-atom of the reactive methylene group is replaced by a grouping which is easily eliminated and selected from the class consisting of a halogen, a carboxylic group and an azo group.

2. A process of color photography which comprises developing a reducible silver salt image in a photographic element by means of an aromatic developing agent in the presence of a color coupler capable of coupling with the development product of said developing agent and correspondin to one of the following isomeric formulae image and a color coupler capable of coupling with the development product of said developin agent and selected from the class consisting of compounds containing a reactive methylene group immediately linked to an azo group and to a group selected from the class consisting of a cyan group. acarbonyl group, a thiocarbonyl group, nitrophenyl, a residue of a nitrogen-containing heterocyclic ring having a free bond in the 2-position with respect to the nitrogen atom, such residue having a free bond in the 4-position, a carbimide group (-C=N) a nitro group and a CHOH group, the hydrazone isomers of said compounds, and said compounds and isomers wherein a H-atom of the reactive'methylene group is replaced by a grouping which is easily eliminated and selected from the class consisting of a halogen, a carboxylic group and an azo group.

5. Photographic developer comprising an aromatic developing agent for a latent silver halide image and a color coupler capable of coupling with the development product of said developing agent and selected from the class consisting of compounds containing a reactive methylene group immediately linked to an azo group and to a group selected from the class consisting of a cyan group, a carbonyl group, a thiocarbonyl group, nitrophenyl, a residue of a nitrogencontaining heterocyclic ring having a free bond in the 2-position with respect to the nitrogen atom, such residue havin a free bond in the 4-position, a carbimide group (C=N--) a nitro group and a -CI-IOI-I- group, the hydrazone isomers of said compounds, and said compounds and isomers wherein a I-I-atom of the reactive methylene group is replaced by a grouping which is easily eliminated and selected from the class consisting of a halogen, a carboxylic group and an azo group.

6. A photographic developer comprising an aromaticdeveloping agent for a latent silver halide image and a color coupler capable of coupling with the development product of said developing agent and correspondin to one of the following isomeric formulae 7. Photographic developer comprising an arcmatic developing agent for a latent silver halide image and an aldose aryl hydrazone.

8. Photographic developer comprising a developing agent for a latent silver halide image and a color couplercapable of couplin with the development product of said developing agent and corresponding to one of the followin iso-' meric formulae OOOH 0 Ni H-N=N CODE JULES EDMOND BEERSMANS.

REFERENCES CITED and The following references are of record in the file of this patent:

UNITED STATES PATENTS Great Britain MB"... Apr. 11., 1939 

1. A PROCESS OF COLOR PHOTOGRAPHY WHICH COMPRISES DEVELOPING A REDUCIBLE SILVER SALT IMAGE IN A PHOTOGRAPHIC ELEMENT BY MEANS OF AN AROMATIC DEVELOPING AGENT IN THE PRESENCE OF A COLOR COUPLER CAPABLE OF COUPLING WITH THE DEVELOPMENT PRODUCT OF SAID DEVELOPING AGENT AND SELECTED FROM THE CLASS CONSISTING OF COMPOUNDS CONTAINING A REACTIVE METHYLENE GROUP IMMEDIATELY LINKED TO AN AZO GROUP AND TO A GROUP SELECTED FROM THE CLASS CONSISTING OF A CYAN GROUP, OF CARBONYL GROUP, A THIOCARBONYL GROUP, NITROPHENYL, A RESIDUE OF A NITROGEN-CONTAINING HETEROCYCLIC RING HAVING A FREE BOND IN THE 2POSITION WITH RESPECT TO THE NITROGEN ATOM, SUCH RESIDUE HAVING A FREE BOND IN THE 4-POSITION, A CARBIMIDE GROUP 